Composite etching stop in semiconductor process integration

Abstract

A new method of forming a composite etching stop layer is described. An etching stop layer is deposited on a substrate wherein the etching stop layer is selected from the group consisting of: silicon carbide, silicon nitride, SiCN, SiOC, and SiOCN. A TEOS oxide layer is deposited by plasma-enhanced chemical vapor deposition overlying the etching stop layer. The composite etching stop layer has improved moisture resistance, better etching selectivity, and lower dielectric constant than other etching stop layers.

What is claimed is:  
     
       1. A method of fabricating an integrated circuit device comprising: 
       depositing a composite etching stop layer overlying a metal line in a substrate wherein said composite etching stop layer comprises a TEOS oxide layer overlying an etching stop layer;  
       depositing a dielectric layer overlying said composite etching stop layer;  
       etching an opening through said dielectric layer stopping at said composite etching stop layer;  
       thereafter removing said composite etching stop layer within said opening; and  
       filling said opening with a conducting layer to complete said fabrication of said integrated circuit device.  
     
     
       2. The method according to  claim 1  wherein said substrate comprises semiconductor device structures including gate electrodes and associated source and drain regions and metallization formed in and on a silicon substrate. 
     
     
       3. The method according to  claim 1  wherein said step of depositing said composite etching stop layer comprises: 
       depositing an etching stop layer selected from the group consisting of: silicon carbide, silicon nitride, SiCN, SiOC, SiOCN, and p-BCB; and  
       depositing said TEOS oxide layer by plasma-enhanced chemical vapor deposition overlying said etching stop layer wherein said TEOS oxide layer provides moisture resistance to said composite etching stop layer.  
     
     
       4. The method according to  claim 3  wherein said etching stop layer has a thickness of between about 200 and 600 Angstroms. 
     
     
       5. The method according to  claim 3  wherein said TEOS oxide layer has a thickness of between about 150 and 500 Angstroms. 
     
     
       6. The method according to  claim 3  wherein said TEOS oxide layer is deposited at less than about 450° C. 
     
     
       7. The method according to  claim 1  wherein said composite etching stop layer has a thickness of between about 300 and 1000 Angstroms. 
     
     
       8. The method according to  claim 1  wherein said dielectric layer is selected from the group consisting of: carbon-based silicate glass, polyarylene ethers, polyimides, and fluorine-doped silicate glass. 
     
     
       9. The method according to  claim 1  wherein said step of etching said opening through said oxide layer and said step of filling said opening comprises a damascene process. 
     
     
       10. A method of forming a composite etching stop layer comprising: 
       depositing an etching stop layer on a copper line in a substrate wherein said etching stop layer is selected from the group consisting of: silicon carbide, silicon nitride, SiCN, SiOC, SiOCN, and p-BCB; and  
       depositing a TEOS oxide layer by plasma-enhanced chemical vapor deposition overlying said etching stop layer to complete said composite etching stop layer.  
     
     
       11. The method according to  claim 10  wherein said substrate comprises semiconductor device structures including gate electrodes and associated source and drain regions formed in and on a silicon substrate. 
     
     
       12. The method according to  claim 10  wherein said composite etching stop layer has a thickness of between about 300 and 1000 Angstroms. 
     
     
       13. The method according to  claim 10  wherein said etching stop layer has a thickness of between about 200 and 600 Angstroms. 
     
     
       14. The method according to  claim 10  wherein said TEOS oxide layer has a thickness of between about 150 and 500 Angstroms. 
     
     
       15. The method according to  claim 10  wherein said TEOS oxide layer is deposited at less than about 450° C. 
     
     
       16. The method according to  claim 10  further comprising: 
       depositing a dielectric layer overlying said composite etching stop layer;  
       etching an opening through said dielectric layer stopping said at composite etching stop layer;  
       thereafter removing said composite etching stop layer within said opening; and  
       filling said opening with a conducting layer to complete fabrication of an integrated circuit device.  
     
     
       17. The method according to  claim 16  wherein said dielectric layer is selected from the group consisting of: carbon-based silicate glass, polyarylene ethers, polyimides, and fluorine-doped silicate glass. 
     
     
       18. The method according to  claim 16  wherein said step of etching said opening through said oxide layer and said step of filling said opening comprises a damascene process. 
     
     
       19. A method of fabricating an integrated circuit device comprising: 
       depositing a composite etching stop layer overlying a copper line in a substrate wherein said depositing comprises:  
       depositing a silicon carbide etching stop layer; and  
       depositing a TEOS oxide layer by plasma-enhanced chemical vapor deposition overlying said silicon carbide etching stop layer;  
       depositing a dielectric layer overlying said composite etching stop layer;  
       etching an opening through said dielectric layer stopping at said composite etching stop layer;  
       thereafter removing said composite etching stop layer within said opening; and  
       filling said opening with a conducting layer to complete said fabrication of said integrated circuit device.  
     
     
       20. The method according to  claim 19  wherein said substrate comprises semiconductor device structures including gate electrodes and associated source and drain regions formed in and on a silicon substrate. 
     
     
       21. The method according to  claim 19  wherein said composite etching stop layer has a thickness of between about 300 and 1000 Angstroms. 
     
     
       22. The method according to  claim 19  wherein said silicon carbide etching stop layer has a thickness of between about 200 and 600 Angstroms. 
     
     
       23. The method according to  claim 19  wherein said TEOS oxide layer has a thickness of between about 150 and 500 Angstroms. 
     
     
       24. The method according to  claim 19  wherein said TEOS oxide layer is deposited at less than about 450° C. 
     
     
       25. The method according to  claim 19  wherein said dielectric layer is selected from the group consisting of: carbon-based silicate glass, polyarylene ethers, polyimides, and fluorine-doped silicate glass. 
     
     
       26. The method according to  claim 19  wherein said step of etching said opening through said oxide layer and said step of filling said opening comprises a damascene process.